The Randomized Intervention for Children with Vesicoureteral Reflux (RIVUR) trial was funded September 30, 2005. The RIVUR study is a multi-center, randomized controlled trial designed to determine whether daily antimicrobial prophylaxis with TMP/SMZ is superior to placebo in preventing recurrent urinary tract infection (UTI) in children diagnosed with vesicoureteral reflux (VUR). RIVUR will also evaluate whether antimicrobial prophylaxis is superior to placebo in modifying the level of renal scarring present at the end of the study. Other aims of the study include evaluating outcomes related to treatment failures, presence of drug resistant bacteria, health-related quality of life, resource utilization, and measures of renal function. Study investigators planned to enroll 600 children with grades l-IV VUR following first or second febrile or symptomatic UTI, but the enrollment target was not met during the original award period. To date, approximately 400 children have been enrolled across all the clinical trial sites. Recruitment projections indicate that the 3-year continuation grant would allow successful enrollment of 600 children , 2-year follow p of the last enrolled child, with time remaining to complete the data analysis and manuscript preparation.